Stabilization of organic compounds



Patented Mar. 31, 1953 STABILIZATION OF ORGANIC COMPOUNDS Joseph A. Chenicek, Bcnsenville, 111., assignor to Universal Oil Products Company,

Chicago, 111.,

a corporation of Delaware No Drawing. Application February 21,1949, Serial No. 77,698

7 Claims.

This invention relates to the stabilization of organic compounds and more particularly to a novel method of improving the effectiveness of known oxidation inhibitors in retarding deterioration of organic compounds in storage or in use, during transfer or during treatment, etc.

Various organic compounds are unstable in storage or in use, while being transferred or during treatment, and form undesirable gums, undergo discoloration, become rancid or otherwise deteriorate due to oxidation, polymerization or other undesired reactions. Included among the organic compounds which undergo such deterioration are, for example, motor fuel, mineral oil, lubricating oil, diesel oil, fuel oil, drying oil, greases, rubber, edible fats and oils, acetylenes and particularly vinyl acetylenes, butadiene, isoprene, styrene, and other vinyl aromatics, various unsaturated alcohols, acids, ketones, etc.

Theinvention is particularly applicable to the stabilization of unsaturated gasolines and still more particularly cracked and polymer gasolines. In storage or during treatment these unsaturated gasolines tend to form undesirable gums. The invention is also applicable to the treatment of aviation gasolines which tend to undergo deterioration due to the addition of tetraethyl lead fluid or due to other components in the gasoline.

The invention is also particularly applicabl to the stabilization of edible fats and oils which generally are of animal or vegetable origin and which tend to become rancid, especially during long periods of storage prior to use. Typical representatives of these edible fats and oils include linseed oil, menhaden oil, cod liver oil, castor oil, olive oil, rapeseed oil, coconut oil, palm oil, corn oil, sesame oil, peanut oil, babassu oil, butter, fat, lard, beef tallow, etc. It is understood that other oils and fats may be treated within the scope of the present invention, including oils and fats which previously have been subjected to various treatments, such as blowing with air, heat treatment, etc.

Still another use of inhibitors is in the treatment of forage crops to protect the vitamin and .food .accessory factor content.

In order to retard such undesirable deterioration, it is general practice to add an oxidation inhibitor to the organic compound. The oxidation inhibitor is usually added in amounts of less than about 1% by weight and generally within the range of from about 0.001% to about 0.1% by'weisht- Particularly satisfactory oxidation inhibitors for use in the stabilization of organic compounds and more particularly motor fuel comprise aro matic amino compounds. Of this group the paminophenols and p-phenylene diamines are being used commercially on a large scale. The preferred p-aminophenol inhibitor comprises N-n-butyl-p-aminophenol, while other satisfactory inhibitors include N-isopropyl-p-aminophenol, N-secbutyl-paminophenol, .N-amyl-paminophenol, etc. During the manufacture of N-n-butyl-p-aminophenol a minor proportion of N-N'-di-n-butyl-p-phenylene diamine is .iormed and the present invention is intended to include such mixtures.

Of the p-phenylene diamines, N-N-di-secbutyl-p-phenylene diamine is being used com-s mercially on a large scale, although it is understood that other satisfactory but not necessarily equivalent oxidation inhibitors include those in which the alkyl radicals attached to one or both of the nitrogen atoms comprise methyl, ethyl, propyl, butyl, tertiary butyl, amyl, etcand that these radicals may be the same or different.

Another class of known oxidation inhibitors include the alkylphenols and particularly the trialkylphenols such as 2,4-dimthyl-6-butyl phenol, etc. Still otherknown inhibitors include .the alkoxyphenols such as 2-tertiary-butyl-4-methoxy-phenol, etc. It is understood that the novel features of the present invention may beapplied to any suitable oxidation inhibitor. "It is understood that the inhibitor for use with .food products must be non-toxic.

Regardless of the particular oxidation inhibitor employed, it has been found that the addition of a quaternary ammonium oxide serves to increase the effectiveness of the inhibitor beyond that which would normally be expected. Thus, the improved potency exceeds that calculated from the accumulated effects of the known oxidation inhibitor and of the quaternary ammonium oxide. This unexpected improvement is referred to as a synergistic effect.

In one embodiment the present invention relates to a method of stabilizing an organic compound subject to oxidative deterioration which comprises adding thereto an oxidation inhibitor and a quaternary ammonium oxide.

In a specific embodiment the present invention relates to a method of stabilizing edible fats and oils which comprises adding thereto an oxigation inhibitor and a quaternary ammonium 0x1 e.

In: another specific embodiment the present invention relatestothe stabilization of :motor fuel 3 which comprises adding thereto an aminophenol oxidation inhibitor and a quaternary ammonium oxide.

The quaternary ammonium oxide of the present invention may be represented by the following general formula: I

I I-O-R R4/ 1 trimethylammonium methoxide, benzyl trimethylammonium ethoxide, benzyl trimethylammonium propoxide, benzyl trimethylammonium butoxide, benzyl trimethylammonium pentoxide, benzyl triethylammonium methoxide, benzyl triethylammonium ethoxide, benzyl triethylammonium propoxide, benzyl triethylammonium butoxide, benzyl triethylammonium pentoxide, tetramethylammonium methoxide, tetramethylammonium ethoxide, tetramethylammonium propoxide, tetramethylammonium butoxide, tetramethylammonium pentoxide, ethyl triethylammonium methoxide, ethyl trimethylammonium ethoxide, ethyl trimethylammonium propoxide, ethyl trimethylammonium butoxide, ethyl trimethylammonium pentoxide, tetraethylammonium alkoxides, tetrapropylammonium alkoxides, tetrabutylammonium alkoxides, tetraamylammonium alkoxides, dibenzyl dialkylammonium alkoxides, alkyl tribenzylammonium alkoxides, similarly substituted compounds in which a phenyl or naphthyl radical comprises one or more of the groups R1, R2, R3 and R4. It is understood that the compounds specifically recited herein represent typical examples of suitable but not necessarily equivalent quaternary ammonium oxides which may be used in accordance with the present invention.

The quaternary ammonium alkoxides hereinbefore set forth may be purchased in the open market or may be prepared in any suitable manner. In general, these compounds are prepared by reacting the corresponding quaternary ammonium'chloride with an aliphatic alcohol in the presence of a basic catalyst. Another method of preparation includes the reaction of the corresponding quaternary ammonium hydroxide with an aliphatic alcohol.

Other classes of compounds included within the scope of the present invention comprise quaiternary ammonium phenoxides and quaternary ammonium benzyloxides. Suitable compounds of these classes include benzyl trimethylammonium phenoxide, benzyl triethylammonium phenoxide, benzyl tripropylammonium phenoxide, benzyl trimethylammonium benzyloxide, benzyl triethylammonium benzyloxide, benzyl tripropylammonium benzyloxide, etc. Here again it is understood that a phenyl or naphthyl radical may replace one or more of the groups R1, R2, R3 and R4. Likewise it is understood, both in connection with the phenoxides and butoxides and in connection with the hereinbefore set forth alkoxides, that the alkyl or aromatic radicals attached to the nitrogen atom may be the same or different.

It is believed that the quaternary ammonium phenoxides and quaternary ammonium'benzyloxides represent novel compositionsof matter minus and the 4 and, therefore, they are being so claimed in the present application. These compounds may be prepared by the reaction of the corresponding quaternary ammonium halide with phenol in one case or with benzyl alcohol in the other case. This reaction is readily effected in the presence of a basic catalyst. Thus, benzyl trimethylammonium phenoxide or benzyloxide may be prepared by the reaction of benzyl trimethylammonium chloride with phenol or benzyl alcohol in the presence of sodium hydroxide. Another method of preparing these catalysts is by the reaction of the. corresponding quaternary ammonium hydroxide with phenol or benzyl alcohol.

Th synergist of the present invention may be added to the organic compound to be stabilized along with the oxidation inhibitor or it may be added before or after the oxidation inhibitor is applied. It is understood that the synergist and inhibitor may also be used in conjunction with other additives which are incorporated in organic compounds for various purposes, such as metal deactivators, antiknock agents, dyes, etc. The synergist may be added in amounts within the same range as hereinbefore set forth for the oxidation inhibitor; that is, in an amount of less than about 1% by weight of the organic compound to be stabilized. Usually, however, the synergist will be added in a smaller amount than the oxidation inhibitor and thus the synergist generally will be utilized in an amount of less than about 0.5% and more particularly in an amount within the range of from about 0.0001% to about 0.1% by weight of the organic compound.

The following example is introduced for the purpose of illustrating further the novelty and utility of the present invention but not with the intention of unduly limitin the same.

0.01% of an oxidation inhibitor comprising N- n-butyl-p-aminophenol when added to a Pennsylvania cracked gasoline increased the induction period of the gasoline from 85 minutes to 555 minutes. 0.01% of a 30% solution of benzyl tri methylammonium butoxide (0.003% by weight of active component) when added to another sample of the same gasoline increased the induction period from 85 minutes to minutes. In order to compare the beneficial results obtained by the addition of the oxidation inhibitor and'of the benzyl trimethylammonium butoxide, the blank induction period of the gasoline is deducted from the induction period obtained upon the addition of the compounds. Thus, the oxidation inhibitor increased the induction period 470 minutes (555 benzyl trimethylammonium butoxide increased the induction period 30 minutes (115 minus 85). Therefore, it would be expected that the addition of both the oxidation inhibitor and the benzyl trimethylammonium butoxide, when used in the same quantities, would give an induction period increase of 500 minutes (470 plus 30). However, upon the addition of ooth the oxidation inhibitor and the benzyl tri'- methylammonium butoxide in the same quantities as hereinbefore set forth to another sample of the same gasohne, an induction period increase of was obtained. It is thus seen that the use of the oxidation inhibitor and the benzyl trimethylammonium butoxide in combination gave an induction period increase greater than would be expected and, therefore, the benzyl trimethylammonium butoxide served as a synergist to increase the potency of the oxidation inhibitor.

I claim as my invention:

1. Unsaturated gasoline subject to oxidative deterioration containing from about 0.001% to about 0.1% by weight of N-n-butyl-p-aminophenol and from about 0.0001% to about 0.1% by weight of a quaternary ammonium alkoxide.

2. Unsaturated gasoline subject to oxidative deterioration containing from about 0.001% to about 0.1% by weight of N-N'-di-sec-butyl-pphenylene diamine and from about 0.0001% to about 0.1 by weight of a quaternary ammonium alkoxide.

3. Unsaturated gasoline containing from about 0.0001% to about 0.1% by weight of a quaternary ammonium alkoxide and from about 0.001% to about 0.1% by weight of an oxidation inhibitor selected from the group consisting of a p-aminophenol and a p-phenylene diamine.

4. The composition of claim 1 further characterized in that said alkoxide is benzyl trimethylammonium butoxide.

5. The composition of claim 2 further characterized in that said alkoxide is benzyl trimethylammonium butoxide.

6. Unsaturated gasoline containing from 6 about 0:0001% to about 0.1% by weight of a quaternary ammonium alkoxide and from about 0.001% to about 0.1% by weight of a p-aminophenol.

'7. Unsaturated gasoline containing from about 0.0001% to about 0.1% by weight of a quaternary ammonium alkoxide and from about 0.001 to about 0.1% by weight of a p-ph-enylene diamine.

JOSEPH A. CHENICEK REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,053,512 Bennett et a1. Sept. 8, 1936 2,084,977 Rogers et a1. June 22, 1937 2,257,752 Lincoln et al Oct. 7, 1941 2,344,886 Lieber Mar. 21, 1944 2,461,972 Fischer Feb. 15, 1949 

3. UNSATURATED GASOLINE CONTAINING FROM ABOUT 0.0001% TO ABOUT 0.1% BY WEIGHT OF A QUANTERNARY AMMONIUM ALKOXIDE AND FROM ABOUT 0.001% TO ABOUT 0.1% BY WEIGHT OF AN OXIDATION INHIBITOR SELECTED FROM THE GROUP CONSISTING OF A P-AMINOPHENOL AND A P-PHENYLENE DIAMINE. 